Cycled light exposure reduces fussing and crying in very preterm infants

The Effect of a Light-Dark Cycle on Premature Infants in the Neonatal Intensive Care Unit: A Randomized Controlled Study

PURPOSE

To investigate potential differences in discharge time, feeding methods and amounts, daily weight gain, vital signs, pain, and comfort levels among preterm infants born at 28-32 weeks' gestation who were hospitalized in the neonatal intensive care unit during long-term follow-up while implementing a light-dark cycle.

DESIGN AND METHODS

This is a randomized controlled study conducted with the support of a day-night cycle in premature infants born at 28-32 weeks' gestation and admitted to the neonatal intensive care unit of a teaching and research hospital affiliated with the Ministry of Health. The study compared the follow-up results from hospitalization to discharge over a period of 8 weeks.

RESULTS

50% of premature infants admitted to the unit are multiple pregnancies. There was no significant difference in discharge weight, comfort level, pain level, vital signs of the infants included in the study (p > 0.05). The optimal development of infant feeding patterns was examinedand it was observed that the study group had significantly improved before the control group in terms of the time to switch to full enteral feeding and oral feeding (p < 0,05). The daily weight gain of the babies was examined, it was seen that the weight gain was higher in the study group compared to the control group (p < 0,05). The mean duration of hospitalization was compared, it was seen that the babies in the study group were discharged significantly earlier (p < 0,05).

CONCLUSION

The study compared the long-term outcomes of premature babies hospitalized in neonatal intensive care and babies exposed to a light-dark cycle and regularly monitored in standard care. The results showed that the babies in the study group had higher daily weight gain and were discharged earlier than the control group. There were also no statistically significant differences in comfort and pain scores, vital signs or oxygen saturation between the study and control groups.

PRACTICE IMPLICATIONS

A light-dark cycle was found to be a feasible and promising intervention for infants at 28-32 weeks' gestation. It was a nurse-led management of care that could be integrated into the usual care of 28-32-week-old babies in neonatal units.

Use of Light Protection Equipment at Night Reduces Time Until Discharge From the Neonatal Intensive Care Unit: A Randomized Interventional Study

Newborn infants' circadian systems are not completely developed and rely on external temporal cues for synchronizing their biological rhythms to the environment. In neonatal intensive care units (NICUs), lighting is usually continuous or irregular and infants are exposed to artificial light at night, which can have negative health consequences. Therefore, the aim of this study was to evaluate the impact of the use of individual light protection equipment at night on the development and growth of preterm neonates. Infants born at less than 37 gestational weeks who no longer needed constant intensive care were admitted into a newborn nursery and randomized to either use eye masks at night (intervention, n = 21) or not (control, n = 20). Infants who used eye protection at night were discharged earlier than those in the control group (8 [5] vs 12 [3.75] days; p < 0.05). A greater variation within the day in heart rate was observed in the intervention group, with lower values of beats per minute at 1400 and 2000 h. There was no significant difference in weight gain between groups. In view of our results and of previous findings present in the literature, we suggest that combining a darkened environment at night with individual light protection devices creates better conditions for the development of preterm infants in the NICU. In addition, eye masks are an affordable and simple-to-use tool that can reduce hospitalization costs by decreasing the number of days spent in the NICU.

A systematic review of chronobiology for neonatal care units: What we know and what we should consider

A Cochrane 2016 review indicated cycled light might benefit neonatal health in hospital. We systematically reviewed chronobiological factors for neonatal health in hospital units, identifying 56 relevant studies on light-dark cycles, feeding, noise, massage therapy, rooming-in, incubators vs. cribs, neonatal units vs. homes, and time-of-day of birth. Empirical evidence for benefits from chronobiology is weaker than expected, including light. Mechanisms of clinical benefits are unclear (e.g., changes to sleep/activity vs. other circadian-regulated processes). Regarding light, studies concerning sleep and circadian-related outcomes predominate; yet, neonatologists may be more interested in weight gain and time spent in hospital. Generalisability of findings is limited as most studies targeted neonates in stable condition and without congenital anomalies. Further research is needed, in particular concerning potential circadian entraining signals such as timing of meals or medications. Longer-term outcomes (regarding e.g., neurodevelopment and infection), and who may be at risk from time-of-day of birth effects and why remain to be explored. Overall, there is promise and ample scope for research into how chronobiological factors affect health in hospitalised neonates.

Not simply a matter of parents-Infants' sleep-wake patterns are associated with their regularity of eating

In adults there are indications that regular eating patterns are related to better sleep quality. During early development, sleep and eating habits experience major maturational transitions. Further, the bacterial landscape of the gut microbiota undergoes a rapid increase in complexity. Yet little is known about the association between sleep, eating patterns and the gut microbiota. We first hypothesized that higher eating regularity is associated with more mature sleep patterns, and second, that this association is mediated by the maturational status of the gut microbiota. To test this hypothesis, we performed a longitudinal study in 162 infants to assess actigraphy, diaries of sleep and eating times, and stool microbiota composition at ages 3, 6 and 12 months. To comprehensively capture infants' habitual sleep-wake patterns, 5 sleep composites that characterize infants' sleep habits across multiple days in their home environment were computed. To assess timing of eating habits, we developed an Eating Regularity Index (ERI). Gut microbial composition was assessed by 16S rRNA gene amplicon sequencing, and its maturation was assessed based on alpha diversity, bacterial maturation index, and enterotype. First, our results demonstrate that increased eating regularity (higher ERI) in infants is associated with less time spent awake during the night (sleep fragmentation) and more regular sleep patterns. Second, the associations of ERI with sleep evolve with age. Third, the link between infant sleep and ERI remains significant when controlling for parents' subjectively rated importance of structuring their infant's eating and sleeping times. Finally, the gut microbial maturational markers did not account for the link between infant's sleep patterns and ERI. Thus, infants who eat more regularly have more mature sleep patterns, which is independent of the maturational status of their gut microbiota. Interventions targeting infant eating rhythm thus constitute a simple, ready-to-use anchor to improve sleep quality.

Effects of the neonatal intensive care environment on circadian health and development of preterm infants

The circadian system in mammals ensures adaptation to the light-dark cycle on Earth and imposes 24-h rhythmicity on metabolic, physiological and behavioral processes. The central circadian pacemaker is located in the brain and is entrained by environmental signals called Zeitgebers. From here, neural, humoral and systemic signals drive rhythms in peripheral clocks in nearly every mammalian tissue. During pregnancy, disruption of the complex interplay between the mother's rhythmic signals and the fetal developing circadian system can lead to long-term health consequences in the offspring. When an infant is born very preterm, it loses the temporal signals received from the mother prematurely and becomes totally dependent on 24/7 care in the Neonatal Intensive Care Unit (NICU), where day/night rhythmicity is usually blurred. In this literature review, we provide an overview of the fetal and neonatal development of the circadian system, and short-term consequences of disruption of this process as occurs in the NICU environment. Moreover, we provide a theoretical and molecular framework of how this disruption could lead to later-life disease. Finally, we discuss studies that aim to improve health outcomes after preterm birth by studying the effects of enhancing rhythmicity in light and noise exposure.

Supporting and Enhancing NICU Sensory Experiences (SENSE), 2nd Edition: An Update on Developmentally Appropriate Interventions for Preterm Infants

The Supporting and Enhancing NICU Sensory Experiences (SENSE) program promotes consistent, age-appropriate, responsive, and evidence-based positive sensory exposures for preterm infants each day of NICU hospitalization to optimize infant and parent outcomes. The initial development included an integrative review, stakeholder input (NICU parents and healthcare professionals), and feasibility focus groups. To keep the program updated and evidence-based, a review of the recent evidence and engagement with an advisory team will occur every 5 years to inform changes to the SENSE program. Prior to the launch of the 2nd edition of the SENSE program in 2022, information from a new integrative review of 57 articles, clinician feedback, and a survey identifying the barriers and facilitators to the SENSE program's implementation in a real-world context were combined to inform initial changes. Subsequently, 27 stakeholders (neonatologists, nurse practitioners, clinical nurse specialists, bedside nurses, occupational therapists, physical therapists, speech-language pathologists, and parents) carefully considered the suggested changes, and refinements were made until near consensus was achieved. While the 2nd edition is largely the same as the original SENSE program, the refinements include the following: more inclusive language, clarification on recommended minimum doses, adaptations to allow for variability in how hospitals achieve different levels of light, the addition of visual tracking in the visual domain, and the addition of position changes in the kinesthetic domain.

Development of the circadian system in early life: maternal and environmental factors

In humans, an adaptable internal biological system generates circadian rhythms that maintain synchronicity of behavior and physiology with the changing demands of the 24-h environment. Development of the circadian system begins in utero and continues throughout the first few years of life. Maturation of the clock can be measured through sleep/wake patterns and hormone secretion. Circadian rhythms, by definition, can persist in the absence of environmental input; however, their ability to adjust to external time cues is vital for adaptation and entrainment to the environment. The significance of these external factors that influence the emergence of a stable circadian clock in the first years of life remain poorly understood. Infants raised in our post-modern world face adverse external circadian signals, such as artificial light and mistimed hormonal cues via breast milk, which may increase interference with the physiological mechanisms that promote circadian synchronization. This review describes the very early developmental stages of the clock and common circadian misalignment scenarios that make the developing circadian system more susceptible to conflicting time cues and temporal disorder between the maternal, fetal, infant, and peripheral clocks.

Precision caffeine therapy for apnea of prematurity and circadian rhythms: New possibilities open up

Caffeine is the globally consumed psychoactive substance and the drug of choice for the treatment of apnea of prematurity (AOP), but its therapeutic effects are highly variable among preterm infants. Many of the molecular underpinnings of the marked individual response have remained elusive yet. Interestingly, the significant association between Clock gene polymorphisms and the response to caffeine therapy offers an opportunity to advance our understanding of potential mechanistic pathways. In this review, we delineate the functions and mechanisms of human circadian rhythms. An up-to-date advance of the formation and ontogeny of human circadian rhythms during the perinatal period are concisely discussed. Specially, we summarize and discuss the characteristics of circadian rhythms in preterm infants. Second, we discuss the role of caffeine consumption on the circadian rhythms in animal models and human, especially in neonates and preterm infants. Finally, we postulate how circadian-based therapeutic initiatives could open new possibilities to promote precision caffeine therapy for the AOP management in preterm infants.

Effect of non-pharmacological interventions on sleep in preterm infants in the neonatal intensive care unit: A protocol for systematic review and network meta-analysis

BACKGROUND

Premature infants are prone to suffer multisystem complications after birth due to the incomplete development of organ tissues and low immunity, and they require a longer period of supervised treatment in the neonatal intensive care unit (NICU). However, due to the specificity of medical care in the NICU, the sleep of preterm infants is highly susceptible that has an impact on the prognosis of preterm infants. Recently, various non-pharmacological interventions have been applied to the sleep of preterm infants in the NICU, which have shown positive outcomes. However, the efficacy and safety of them are unclear. This study aims to evaluate the effects of non-pharmacological interventions on sleep in preterm infants in the NICU through a network meta-analysis.

METHODS

Randomized controlled trials of non-pharmacological interventions on sleep in preterm infants in the NICU published before September 2021 will be searched in online databases, including the Chinese Scientific Journal Database, China National Knowledge Infrastructure Database, Wanfang, China Biomedical Literature Database, PubMed, Cochrane Library, Embase, and Web of Science. Two researchers will be independently responsible for screening and selecting eligible literatures, extracting data and evaluating the risk of bias in the included studies. Stata 14.0 software will be used for data analysis.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide comprehensive and reliable evidence-based references for the efficacy and safety in different non-pharmacological interventions on sleep in preterm infants in the NICU.

Actigraphy in sleep research with infants and young children: Current practices and future benefits of standardized reporting

Actigraphy is a cost-efficient method to estimate sleep-wake patterns over long periods in natural settings. However, the lack of methodological standards in actigraphy research complicates the generalization of outcomes. A rapidly growing methodological diversity is visible in the field, which increasingly necessitates the detailed reporting of methodology. We address this problem and evaluate the current state of the art and recent methodological developments in actigraphy reporting with a special focus on infants and young children. Through a systematic literature search on PubMed (keywords: sleep, actigraphy, child *, preschool, children, infant), we identified 126 recent articles (published since 2012), which were classified and evaluated for reporting of actigraphy. Results show that all studies report on the number of days/nights the actigraph was worn. Reporting was good with respect to device model, placement and sleep diary, whereas reporting was worse for epoch length, algorithm, artefact identification, data loss and definition of variables. In the studies with infants only (n = 58), the majority of articles (62.1%) reported a recording of actigraphy that was continuous across 24 hr. Of these, 23 articles (63.9%) analysed the continuous 24-hr data and merely a fifth used actigraphy to quantify daytime sleep. In comparison with an evaluation in 2012, we observed small improvements in reporting of actigraphy methodology. We propose stricter adherence to standards in reporting methodology in order to streamline actigraphy research with infants and young children, to improve comparability and to facilitate big data ventures in the sleep community.

Beginning to See the Light: Lessons Learned From the Development of the Circadian System for Optimizing Light Conditions in the Neonatal Intensive Care Unit

The circadian timing system optimizes health by temporally coordinating behavior and physiology. During mammalian gestation, fetal circadian rhythms are synchronized by the daily fluctuations in maternal body temperature, hormones and nutrients. Circadian disruption during pregnancy is associated with negative effects on developmental outcomes in the offspring, highlighting the importance of regular and robust 24-h rhythms over gestation. In the case of preterm birth (before 37 weeks of gestation), maternal cues no longer synchronize the neonate's circadian system, which may adversely affect the neonate. There is increasing evidence that introducing robust light-dark cycles in the Neonatal Intensive Care Unit has beneficial effects on clinical outcomes in preterm infants, such as weight gain and hospitalization time, compared to infants exposed to constant light or constant near-darkness. However, the biological basis for these effects and the relationship with the functional and anatomical development of the circadian system is not fully understood. In this review, we provide a concise overview of the effects of light-dark cycles on clinical outcomes of preterm neonates in the NICU and its alignment with the development of the circadian system.

Inexpensive Home Infrared Living/Environment Sensor with Regional Thermal Information for Infant Physical and Psychological Development

The use of home-based image sensors for biological and environmental monitoring provides novel insight into health and development but it is difficult to evaluate people during their normal activities in their home. Therefore, we developed a low-cost infrared (IR) technology-based motion, location, temperature and thermal environment detection system that can be used non-invasively for long-term studies in the home environment. We tested this technology along with the associated analysis algorithm to visualize the effects of parental care and thermal environment on developmental state change in a non-human primate model, the common marmoset (Callithrix jacchus). To validate this system, we first compared it to a manual analysis technique and we then assessed the development of circadian rhythms in common marmosets from postnatal day 15–45. The semi-automatically tracked biological indices of locomotion velocity (BV) and body surface temperature (BT) and the potential psychological index of place preference toward the door (BD), showed age-dependent shifts in circadian phase patterns. Although environmental variables appeared to affect circadian rhythm development, principal component analysis and signal superimposing imaging methods revealed a novel phasic pattern of BD-BT correlation day/night switching in animals older than postnatal day 38 (approximately equivalent to one year of age in humans). The origin of this switch was related to earlier development of body temperature (BT) rhythms and alteration of psychological behavior rhythms (BD) around earlier feeding times. We propose that this cost-effective, inclusive sensing and analytic technique has value for understanding developmental care conditions for which continual home non-invasive monitoring would be beneficial and further suggest the potential to adapt this technique for use in humans.

Do NICU developmental care improve cognitive and motor outcomes for preterm infants? A systematic review and meta-analysis

Background

The aim of this study was to review the effects of developmental care in neonatal intensive care unit (NICU) setting on mental and motor development of preterm infants.

Method

We searched PubMed, EMBASE, CINAHL, Scopus, Web of Science and Cochrane library until October 8th 2017, and included randomized controlled trials that assessed effects of developmental care in NICU on mental and motor development of preterm infants at 12 and 24 months of age, using the Bayley scale of infant development in this systematic review. In addition, data were pooled by random effects model and Standardized Mean Difference (SMD) with 95% confidence intervals (CI), calculated for meta-analysis.

Results

Twenty one studies were eligible to be included in this systematic review; however, only thirteen studies had data suitable for meta-analysis. According to statistical analysis, developmental care in NICU improved mental developmental index (MDI) (standardized mean difference [SMD] 0.55, 95% confidence interval [CI] 0.23–0.87; p < 0.05), and psychomotor developmental index (PDI) (SMD 0.33, [CI] 95% CI 0.08–0.57; p < 0.05) of BSID at 12 months of age and PDI at 24 months of age (SMD 0.15, 95% CI -0.02–0.32; p < 0.1) of preterm infants. However, the benefit was not detected at 24 months of age on MDI (SMD 0.15, 95% CI -0.05–0.35; p = 0.15).

Conclusion

Current evidence suggests that developmental care in only NICU setting could have significant effect on mental and motor development of preterm infants, especially at 12 months of age. However, because of clinical heterogeneity, more studies are needed to evaluate the effects of developmental NICU care in the development of preterm infants.

Human milk as "chrononutrition": implications for child health and development

Human biology follows recurring daily rhythms that are governed by circadian cues in the environment. Here we show that human milk is a powerful form of "chrononutrition," formulated to communicate time-of-day information to infants. However, 85% of breastfed infants in the US consume some milk that does not come directly from the breast but is pumped and stored in advance of feeding. Expressed milk is not necessarily circadian-matched (e.g., an infant might drink breastmilk pumped in the evening on the following morning). Ingesting mistimed milk may disrupt infants' developing circadian rhythms, potentially contributing to sleep problems and decreased physiological attunement with their mothers and environments. Dysregulated circadian biology may compromise infant health and development. Despite wide-ranging public health implications, the timing of milk delivery has received little empirical study, and no major pediatric or public health organization has issued recommendations regarding the circadian-matching of milk. However, potential adverse developmental and health consequences could be ameliorated by simple, low-cost interventions to label and circadian-match stored milk. The current paper reviews evidence for human milk as chrononutrition and makes recommendations for future research, practice, and policy.

Supporting and enhancing NICU sensory experiences (SENSE): Defining developmentally-appropriate sensory exposures for high-risk infants

INTRODUCTION

There is evidence to support the use of positive sensory exposures (music, touch, skin-to-skin) with preterm infants in the neonatal intensive care unit (NICU), but strategies to improve their consistent use are lacking. The Supporting and Enhancing NICU Sensory Experiences (SENSE) program was developed to promote consistent, age-appropriate, responsive, and evidence-based positive sensory exposures for the preterm infant every day of NICU hospitalization.

METHODS

A systematic and rigorous process of development of the SENSE program included an integrative review of evidence on sensory exposures in the NICU, stakeholder feedback, expert opinion, and focus groups.

RESULTS

SENSE implementation materials consist of parent education materials, tailored doses of sensory exposures for each postmenstrual age, an infant assessment of tolerance, bedside logs and implementation considerations for integrating the SENSE program into the NICU.

DISCUSSION

Research is needed to evaluate the SENSE program as an implementation strategy and to assess its impact on parent and infant outcomes.

Sleep and prematurity: sleep outcomes in preterm children and influencing factors

BACKGROUND

Sleep undergoes changes from birth to adulthood, while sleep disorders are associated with various cognitive deficiencies in childhood. In parallel, prematurity is known to predispose to poor neurodevelopmental outcomes. Our aim is to provide literature data about factors influencing sleep in the premature infants and sleep outcomes in this population.

METHODS

A systematic review was conducted using a variety of health-related databases. Original research papers were considered and no year-of-publication restriction was placed.

RESULTS

In total, 22 articles fulfilled our selection criteria. Available studies present remarkable heterogeneity in terms of methodological design. Compared to full term, premature infants exhibit significant differences in sleep structure, which mainly include differences in electroencephalographic spectral values, in total sleep time and in arousal threshold. Furthermore, prematurity seems to be a risk factor of sleep breathing disorders in childhood and adolescence. Data about the effect of methylxanthines and the environment of neonatal intensive care unit is controversial. With regard to the impact of prematurity-related sleep disorders on future neurodevelopment, available research papers are generally few.

CONCLUSIONS

The alterations in sleep patterns are an outcome of prematurity (immaturity of nervous system) as well as of postnatal factors and comorbidities. Sleep problems in this population of infants seems to be a missing piece of the puzzle of impaired neurodevelopment. Future studies should focus on interventions to improve sleep hygiene and limit neurodevelopmental problems.

Infant crying and the calming response: Parental versus mechanical soothing using swaddling, sound, and movement

Background

Frequent infant crying is associated with parental exhaustion, depression, or even infant hospitalization and shaken baby syndrome. Effective prompt soothing methods are lacking for infants under 6 months. We examined whether swaddling, sound, and movement evoked an immediate calming response (CR) when parents soothed their infants and using a smart crib, and whether infant age affected the CR.

Methods

Infants’ CR was assessed in a community sample of 69 infants (0–6 months) in a counterbalanced experiment with two conditions (parent, smart crib) each composed of three two-minute phases (baseline, supine, soothing). During baseline 1, parent and infant were sitting together; in supine 1, fussiness was elicited by putting the infant suddenly supine, followed by parental soothing (shushing and jiggling of the swaddled infant). Baseline 2, supine 2, and soothing by the crib followed. Fussiness was observed and infant heart rate (HR) and heart rate variability (HRV) were recorded. The CR was operationalized as decreased fussiness and HR, and increased HRV during soothing compared to lying supine.

Results

Infant fussiness and HR were lower in both soothing phases compared to the supine phases. Infant HRV tended to be higher during parental soothing than during supine, but did not significantly differ between mechanical soothing and supine. Younger infants responded with a stronger CR (decreased fussiness and increased HRV) to parental soothing, but not to mechanical soothing. For HR, infants’ CR was stronger in the crib than in the parent condition, whereas for HRV, infants’ CR was stronger in the parent condition. For fussiness, infants’ CR tended to be stronger in the parent condition.

Conclusion

Parental and mechanical soothing using swaddling, sound, and movement promptly induced a CR in infants. This has important clinical implications for soothing fussy and crying infants. Future studies should investigate the effects of parental versus mechanical soothing in the home setting.

Potential Circadian Rhythms in Oligodendrocytes? Working Together Through Time

Oligodendrocytes (OL) are the only myelinating cells of the central nervous system thus interferences, either environmental or genetic, with their maturation or function have devastating consequences. Albeit so far neglected, one of the less appreciated, nevertheless possible, regulators of OL maturation and function is the circadian cycle. Yet, disruptions in these rhythms are unfortunately becoming a common "disorder" in the today's world. The temporal patterning of behaviour and physiology is controlled by a circadian timing system based in the anterior hypothalamus. At the molecular level, circadian rhythms are generated by a transcriptional/translational feedback system that regulates transcription and has a major impact on cellular function(s). Fundamental cellular properties/functions in most cell types vary with the daily circadian cycle: OL are unlikely an exception! To be clear, the presence of circadian oscillators or the cell-specific function(s) of the circadian clock in OL has yet to be defined. Furthermore, we wish to entertain the idea of links between the "thin" evidence on OL intrinsic circadian rhythms and their interjection(s) at different stages of lineage progression as well as in supporting/regulating OL crucial function: myelination. Individuals with intellectual and developmental syndromes as well as neurodegenerative diseases present with a disrupted sleep/wake cycle; hence, we raise the possibility that these disturbances in timing can contribute to the loss of white matter observed in these disorders. Preclinical and clinical work in this area is needed for a better understanding of how circadian rhythms influence OL maturation and function(s), to aid the development of new therapeutic strategies and standards of care for these patients.

Randomized Controlled Trial on the Effects of Morning versus Evening Primary Vaccination on Episodes of Hypoxemia and Bradycardia in Very Preterm Infants

BACKGROUND

Hypoxemia and bradycardia occur frequently in preterm infants, but are incompletely understood. They are more prevalent during infections and following immunization. Data on adults suggested an increased immune response if subjects slept following vaccination, suggesting an interaction between circadian rhythm and the immune system. Whether this holds true for preterm infants with their less well-established circadian rhythm is unclear.

OBJECTIVE

Do infants born at 26-30 weeks' gestation and having received their first routine hexavalent vaccination in the morning have a lower cardiorespiratory event rate (CER) after vaccination than those receiving it in the evening?

METHODS

Twenty-six infants were randomized to an evening versus morning vaccination group in a pilot and main study with 10 and 16 participants, respectively. Pulse oximeter saturation, actigraphy, and rectal temperature were obtained for 24 h before and after vaccination. Blood samples for vaccination titers were taken before vaccination and during a follow-up examination in our outpatient clinic; another blood sample was taken 24 h after vaccination to determine inflammatory markers.

RESULTS

Vaccination led to an increase in CER in both groups, but there was no difference in CER between the morning and evening groups. Vaccination titers for Bordetella pertussis were increased in both groups, with no difference in inflammatory markers 24 h after vaccination. Body temperature increased in both groups after vaccination. Participants in the evening group slept longer after vaccination.

CONCLUSIONS

We did not identify a difference in CER between morning and evening vaccination but could confirm increased body temperatures and vaccination titers following vaccination.

Rhythms of life: circadian disruption and brain disorders across the lifespan

Many processes in the human body - including brain function - are regulated over the 24-hour cycle, and there are strong associations between disrupted circadian rhythms (for example, sleep-wake cycles) and disorders of the CNS. Brain disorders such as autism, depression and Parkinson disease typically develop at certain stages of life, and circadian rhythms are important during each stage of life for the regulation of processes that may influence the development of these disorders. Here, we describe circadian disruptions observed in various brain disorders throughout the human lifespan and highlight emerging evidence suggesting these disruptions affect the brain. Currently, much of the evidence linking brain disorders and circadian dysfunction is correlational, and so whether and what kind of causal relationships might exist are unclear. We therefore identify remaining questions that may direct future research towards a better understanding of the links between circadian disruption and CNS disorders.

Timing for the Introduction of Cycled Light for Extremely Preterm Infants: A Randomized Controlled Trial

Day-night cycled light improves health outcomes in preterm infants, yet the best time to institute cycled light is unclear. The hypothesis of this study was that extremely preterm infants receiving early cycled light would have better health and developmental outcomes than infants receiving late cycled light. Infants born at ≤28 weeks gestation were randomly assigned to early cycled light (ECL) starting at 28 weeks postmenstrual age [PMA] or late cycled light (LCL), starting at 36 weeks PMA. Daylight was 200-600 lux and night was 5-30 lux. Primary outcomes were weight over time and length of hospitalization. Secondary outcomes were hospital costs, sleep development, and neurodevelopment at 9, 18, and 24 months corrected age. Of 121 infants randomized, 118 were included in analysis. Weight gain in the two groups did not differ significantly but increased across time in both groups. In PMA weeks 36-44, the mean weight gain was 193.8 grams in the ECL group compared to 176.3 grams in the LCL group. Effect sizes for weight were Cohen d = 0.26 and 0.36 for 36 and 44 weeks PMA. Infants in the ECL group went home an average of 5.5 days earlier than the LCL group, but this difference was not statistically significant. There were no group differences on neurodevelopmental outcomes. Although statistically non-significant, clinically important differences of improved weight gain and decreased hospital stay were observed with ECL. The small observed effect sizes on weight during hospitalization should be considered in future cycled light research with extremely preterm infants. © 2017 Wiley Periodicals, Inc.

Effects of Cycled Lighting Versus Continuous Near Darkness on Physiological Stability and Motor Activity Level in Preterm Infants

BACKGROUND

Preterm infants generally spend weeks in the neonatal intensive care unit where light intensity can fluctuate as well as be high, leading to physiological instability and increased motor activity in these infants. To date, 2 lighting control methods have been studied: cycled lighting and continuous near darkness. The most appropriate method of lighting is still unknown due to ambivalent results from the studies that have assessed these 2 interventions.

OBJECTIVE

To compare the effects of cycled lighting versus continuous near darkness on physiological stability and motor activity level in preterm infants born between 28 and 32 weeks of gestation.

METHODS

A randomized clinical trial was conducted to compare physiological stability and motor activity level in preterm infants assigned to cycled lighting or continuous near darkness. Thirty-eight participants were recruited and randomly assigned to one of the lighting conditions for 24 hours. Physiological stability was measured using the Stability of the Cardiorespiratory System in Premature Infants (SCRIP) score, the means, and the coefficient of variation of each physiological parameter measured. The level of motor activity was measured with an accelerometer.

RESULTS

There were no significant differences between the 2 groups with regard to physiological stability measured by the SCRIP score, means, and coefficient of variation as well as motor activity level. Participants in both groups were physiologically stable and their motor activity level was comparable.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Neither cycled lighting nor continuous near darkness negatively impacted infant's physiologic stability and motor activity level. Further research is required to identify the most appropriate lighting control method for preterm infants born between 28 and 32 weeks of gestation.

The effect of cycled lighting in the intensive care unit on sleep, activity and physiological parameters: A pilot study

Patients in intensive care suffer from severe illnesses or injuries and from symptoms related to care and treatments. Environmental factors, such as lighting at night, can disturb patients' circadian rhythms. The aim was to investigate whether patients displayed circadian rhythms and whether a cycled lighting intervention would impact it. In this pilot study (N=60), a cycled lighting intervention in a two-bed patient room was conducted. An ordinary hospital room functioned as the control. Patient activity, heart rate, mean arterial pressure and body temperature were recorded. All data were collected during the patients' final 24h in the intensive care unit. There was a significant difference between day and night patient activity within but not between conditions. Heart rates differed between day and night significantly for patients in the ordinary room but not in the intervention room or between conditions. Body temperature was lowest at night for all patients with no significant difference between conditions. Patients in both conditions had a natural circadian rhythm; and the cycled lighting intervention showed no significant impact. As the sample size was small, a larger repeated measures study should be conducted to determine if other types of lighting or environmental factors can impact patients' well-being.

Environmental factors influencing biological rhythms in newborns: From neonatal intensive care units to home

Photic and non-photic environmental factors are suggested to modulate the development of circadian rhythms in infants. Our aim is to evaluate the development of biological rhythms (circadian or ultradian) in newborns in transition from Neonatal Intensive Care Units (NICU) to home and along the first 6 months of life, to identify masking and entraining environment factors along development. Ten newborns were evaluated in their last week inside the NICU and in the first week after being delivered home; 6 babies were also followed until 6 months of corrected age. Activity, recorded with actimeters, wrist temperature and observed sleep and feeding behavior were recorded continuously along their last week inside the NICU and in the first week at home and also until 6 months of corrected age for the subjects who remained in the study. Sleep/wake and activity/rest cycle showed ultradian patterns and the sleep/wake was strongly influenced by the 3 h feeding schedule inside the NICU, while wrist temperature showed a circadian pattern that seemed no to be affected by environmental cycles. A circadian rhythm emerges for sleep/wake behavior in the first week at home, whereas the 3 h period vanishes. Both activity/rest and wrist temperature presented a sudden increase in the contribution of the circadian component immediately after babies were delivered home, also suggesting a masking effect of the NICU environment. We found a positive correlation of postconceptional age and the increase in the daily component of activity and temperature along the following 6 months, while feeding behavior became arrhythmic.

The NICU Lighted Environment

Lighting technologies are rapidly evolving, creating many opportunities for good lighting within the NICU. With the widespread adoption of advanced solid-state lighting technologies, lighting no longer needs to be static. Rather, lighting systems can be more easily adjusted to the different and changing visual and non-visual needs of the professional staff, infants and family members throughout the 24-hour day. This paper provides a conceptual framework for defining good lighting in the NICU, recognizing the needs of various constituent groups, each with very different needs from the lighting. Several other papers on the topic of lighting for various constituent groups at different times of the day in the NICU are summarized. Attention is given specifically to the Recommended Standards for Newborn ICU Design, a consensus standard developed by a wide range of experts, to help the reader translate this conceptual framework to practice.

Cycled light in the intensive care unit for preterm and low birth weight infants

BACKGROUND

Potential benefits and harms of different lighting in neonatal units have not been quantified.

OBJECTIVES

• To determine effectiveness and safety of cycled light (CL) (approximately 12 hours of light on and 12 hours of light off) for growth in preterm infants at three and six months' corrected age (CA).• In separate analyses, to compare effects of CL with those of irregularly dimmed light (DL) or near darkness (ND), and effects of CL with those of continuous bright light (CBL), on growth in preterm infants at three and six months' CA.• To assess, in subgroup analyses, the effectiveness and safety of CL (vs control interventions (DL, ND and CBL)) introduced at different postmenstrual ages (PMAs) - before 32 weeks', at 32 weeks' and from 36 weeks' PMA - and to compare effectiveness and safety of CL for small for gestational age (GA) infants versus appropriately grown infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 12), MEDLINE via PubMed (1966 to January 2016), Embase (1980 to January 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to January 2016). We searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised trials of CL versus ND or CBL in preterm and low birth weight infants.

DATA COLLECTION AND ANALYSIS

We performed data collection and analyses according to the methods of the Cochrane Neonatal Review Group. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

We identified one additional study enrolling 38 participants for inclusion in this update, for a total of nine studies reporting on 544 infants. In general, the quality of the studies was low, mainly owing to lack of blinding and small sample sizes.Six studies enrolling 424 infants compared CL versus ND. No study reported on weight at three or six months. One study (n = 40) found no statistically significant difference in weight at four months between CL and ND groups. In another study (n = 62), the ratio of day-night activity before discharge favoured the CL group (mean difference (MD) 0.18, 95% confidence interval (CI) 0.17 to 0.19), indicating 18% more activity during the day than during the night in the CL group compared with the ND group. Two studies (n = 189) reported on retinopathy of prematurity (stage ≥ 3) and reported no statistically significant differences between CL and ND groups (typical risk ratio (RR) 0.53, 95% CI 0.25 to 1.11, I(2) = 0%; typical risk difference (RD) -0.09, 95% CI -0.19 to 0.01, I(2) = 0%). Two studies (n = 77) reported length of hospital stay (days) and noted a significant reduction in length of stay between CL and ND groups favouring the CL group (weighted mean difference (WMD) -13 days, 95% CI -23 to -2, I(2) = 0%; no heterogeneity). The quality of the evidence according to GRADE was low for this outcome. One study (n = 37) reported less crying at 11 weeks' corrected age (CA) in the CL group compared with the ND group (MD -0.57 hours/24 h, 95% CI -1.09 to -0.05). Tests for heterogeneity were not applicable.Three studies enrolling 120 infants compared CL versus CBL. Two studies (n = 79) reported significantly shorter length of stay in the CL group compared with the CBL group (WMD -16.5 days, 95% CI -26.2 to -6.8, I(2) = 0%; no heterogeneity). The quality of the evidence according to GRADE was low for this outcome. One study (n = 41) reported higher mean weight at three months' CA among infants cared for in the CL nursery (P value < 0.02) and a lower mean number of hours spent awake in 24 hours at three months of age (P value < 0.005). Data could not be entered into RevMan or GRADE. One study (n = 41) reported shorter time on the ventilator in the CL compared with the CBL group (MD -18.2 days, 95% CI -31.40 to -5.0). One study (n = 41) reported a shorter time to first oral feeding in the CL group (MD -6.8 days, 95% CI -13.29 to -0.31). We identified no safety issues.

AUTHORS' CONCLUSIONS

Trials assessing the effects of CL have enrolled 544 infants. No study reported on our primary outcome of weight at three or six months. Results from one additional study strengthen our findings that CL versus CBL shortens length of stay, as does CL versus ND. The quality of the evidence on both comparisons for this outcome according to GRADE was low. Future research should focus on comparing CL versus ND.

Immediate effects of phototherapy on sleep in very preterm neonates: an observational study

Process C (internal clock) and Process S (sleep-wake homeostasis) are the basis of sleep-wake regulation. In the last trimester of pregnancy, foetal heart rate is synchronized with the maternal circadian rhythm. At birth, this interaction fails and an ultradian rhythm appears. Light exposure is a strong factor influencing the synchronization of sleep-wake processes. However, little is known about the effects of phototherapy on the sleep rhythm of premature babies. It was hypothesized that sleep in preterm infants would not differ during phototherapy, but that a maturation effect would be seen. Sleep states were studied in 38 infants born < 32 weeks gestational age and/or < 1 500 g birth weight. Videos of 3 h were taken over the first 5 days of life. Based on breathing and movement patterns, behavioural states were defined as: awake; active sleep; or quiet sleep. Videos with and without phototherapy were compared for amounts of quiet sleep and active states (awake + active sleep). No significant association between phototherapy and amount of quiet sleep was found (P = 0.083). Analysis of videos in infants not under phototherapy revealed an increase in time spent awake with increasing gestational age. The current data suggest that the ultradian rhythm of preterm infants seems to be independent of phototherapy, supporting the notion that sleep rhythm in this population is mainly driven by their internal clock.

Let there be light and darkness: findings from a prestudy concerning cycled light in the intensive care unit environment

The present study reports findings concerning light in an intensive care unit setting presented from 3 aspects, giving a wide view. The first part is a systematic review of intervention studies concerning cycled light compared with dim light/noncycled light. The findings showed that cycled light may be beneficial to preterm infant health. Second, a lighting intervention in the intensive care unit is presented, comparing and assessing experience of this lighting environment with that of an ordinary room. Significant differences were shown in hedonic tone, favoring the intervention environment. In the third part, measured illuminance, luminance, and irradiance values achieved in the lighting intervention room and ordinary room lighting are reported.

Behavioral observation differentiates the effects of an intervention to promote sleep in premature infants: a pilot study

PURPOSE

Sleep and ongoing cycling of sleep states are required for neurosensory processing, learning, and brain plasticity. Many aspects of neonatal intensive care environments such as handling for routine and invasive procedures, bright lighting, and noise can create stress, disrupt behavior, and interfere with sleep in prematurely born infants. The study empirically investigated whether a 30-minute observation of infant sleep states and behavior could differentiate an intervention to promote sleep in premature infants with feeding difficulties relative to conventional care (standard positioning, standard crib mattress [SP]). We included an intervention to determine the ability of the method to discriminate treatments and generate a benchmark for future improvements. The intervention, a conformational positioner (CP), is contoured around the infant to provide customized containment and boundaries. To more fully verify the 30-minute observational sleep results, standard polysomnography was conducted simultaneously and sleep outcomes for the 2 modalities were compared.

SUBJECTS

In a randomized crossover clinical trial, 25 infants, 31.5 ± 0.6 weeks' gestational age and 38.4 ± 0.6 weeks at the study, with gastrointestinal conditions or general feeding difficulties used each intervention during an overnight neonatal intensive care unit sleep study.

METHODS

Infant sleep states and behaviors were observed during two 30-minute periods--that is, on the positioner and mattress--using the naturalistic observation of newborn behavior. Two certified developmental care nurses assessed sleep state, self-regulatory, and stress behaviors during 2-minute intervals and summed over 30 minutes. Sleep characteristics from standard polysomnography were measured at the time of behavior observations.

RESULTS

Infants on CP spent significantly less time in alert, active awake, or crying states by observation compared with SP. Surgical subjects spent more time awake, active awake, or crying and displayed a higher number of behavior state changes than the nonsurgical infants. The percentage of time in observed deep sleep and quiet sleep was correlated with both percentage sleep efficiency (r = 0.78) and fewer state shifts per hour (r = -0.65) from electroencephalogram (EEG). Sleep efficiency by EEG was greater on CP versus SP.

CONCLUSIONS

The CP enabled sleep compared with the standard mattress (SP) over 30-minute observation periods. Sleep status from behavioral observation was verified by standard EEG-based sleep techniques. Behavioral observation of sleep states may be a useful strategy for measuring the effectiveness of strategies to facilitate sleep in premature infants. Surgical subjects may benefit from additional interventions to promote sleep.

Very preterm infants show earlier emergence of 24-hour sleep-wake rhythms compared to term infants

BACKGROUND

Previous studies show contradictory results about the emergence of 24-h rhythms and the influence of external time cues on sleep-wake behavior in preterm compared to term infants.

AIMS

To examine whether very preterm infants (<32 weeks of gestational age) differ in their emergence of the 24-h sleep-wake rhythm at 5, 11 and 25 weeks corrected age compared to term infants and whether cycled light conditions during neonatal intermediate care affects postnatal 24-h sleep-wake rhythms in preterm infants.

STUDY DESIGN

Prospective cohort study with nested interventional trial.

SUBJECTS

34 preterm and 14 control term infants were studied. During neonatal hospitalization, preterm infants were randomly assigned to cycled light [7 am-7 pm lights on, 7 pm-7 am lights off, n=17] or dim light condition [lights off whenever the child is asleep, n=17].

OUTCOME MEASURES

Sleep and activity behavior recorded by parental diary and actigraphy at 5, 11 and 25 weeks corrected age.

RESULTS

Sleep at nighttime and the longest consolidated sleep period between 12 pm-6 am was longer (mixed model analysis, factor group: p=0.02, resp. p=0.01) and activity at nighttime was lower (p=0.005) at all ages in preterm compared to term infants. Cycled light exposed preterm infants showed the longest nighttime sleep duration. Dim light exposed preterm infants were the least active.

CONCLUSIONS

Preterm infants show an earlier emergence of the 24-h sleep-wake rhythm compared to term infants. Thus, the length of exposure to external time cues such as light may be important for the maturation of infant sleep-wake rhythms. Trial registry number: This trial has been registered at www.clinicaltrials.gov (identifier NCT01513226).

Cycled light in the intensive care unit for preterm and low birth weight infants

BACKGROUND

The potential benefits and harms of different lighting in neonatal units have not been quantified.

OBJECTIVES

To compare the effectiveness of cycled lighting (CL) (approximately 12 hours of light on and 12 hours of light off) with irregularly dimmed light (DL) or near darkness (ND) and with continuous bright light (CBL) on growth in preterm infants at three and six months of age.

SEARCH METHODS

We conducted electronic searches of the literature (in January 2013) of the Cochrane Central Register of Controlled Trials, Issue 12, 2012 (CENTRAL), MEDLINE, EMBASE, CINAHL and abstracts from Pediatric Academic Societies' annual meetings. We searched Controlled-trials.com and Clinicaltrials.gov for ongoing trials and abstracts from the Pediatric Academic Societies (PAS) Annual Meetings (2000 to 2013) using the Abstracts2view website on 10 May 2013.

SELECTION CRITERIA

Randomized or quasi-randomised trials of CL versus ND or CBL in preterm and low birth weight infants.

DATA COLLECTION AND ANALYSIS

We performed data collection and analyses according to the methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

Six studies enrolling 424 infants compared CL versus ND (including one additional trial identified in this update that enrolled 37 infants). No study reported on weight at three or six months. In one study (n = 40), there was no statistically significant difference in weight at four months between the CL and ND groups. In another study (n = 62), the ratio of day-night activity prior to discharge favoured the CL group (mean difference (MD) 0.18, 95% confidence interval (CI) 0.17 to 0.19) indicating 18% more activity during the day than during the night in the CL group compared with the ND group. Two studies (n = 189) reported on retinopathy of prematurity (stage ≥ 3). There was no statistically significant difference between the CL and ND groups (typical risk ratio (RR) 0.53, 95% CI 0.25 to 1.11, I(2) = 0%; typical risk difference (RD) -0.09, 95% CI -0.19 to 0.01, I(2) = 0%). Two studies (n = 77) reported on length of hospital stay (days). There was a significant reduction in the length of stay between the CL and the ND groups favouring the CL group (MD -13 days, 95% CI -2 to -23). One study (n = 37) reported on less crying at 11 weeks' corrected age (CA) in the CL group compared with the ND group (MD -0.57 hours/24 hours, 95% CI -1.09 to -0.05).There was no heterogeneity for this outcome (I(2) = 0%).Two studies enrolling 82 infants compared CL versus CBL. One study (n = 41) reported higher mean weight at three months' CA in infants cared for in the CL nursery (P value < 0.02) and lower mean number of hours spent awake in 24 hours at three months of age (P value < 0.005). One study (n = 41) reported shorter time on ventilator in the CL compared with the CBL group (MD -18.2 days, 95% CI -31.40 to -5.0). One study (n = 41) reported a shorter time to first oral feeding in the CL group (MD -6.8 days, 95% CI -13.29 to -0.31).For many outcomes, the trends favoured CL versus ND as well as CL versus CBL.We identified no safety issues.

AUTHORS' CONCLUSIONS

Trials assessing the effect of CL have enrolled 506 infants. Trends for many outcomes favoured CL compared with ND and CL compared with CBL. The studies may have lacked significance due to a lack of statistical power. Future research should focus on comparing CL to ND.

Neonatal physiological and behavioral stress during neurological assessment

Physiological and behavioral effects of evaluative handling procedures were studied in 72 newborn infants: 36 preterm (30-35 weeks of gestation) and 36 full-term neonates (39-41 weeks of gestation). While the neurological assessment was physiologically and behaviorally destabilizing to both age groups, preterm subjects had higher heart rate (P < .001), greater increase in blood pressure (P < .01); decreased peripheral oxygenation inferred from mottled skin color (P < .001); and higher frequencies of finger splay (P < .001), arm salute (P < .01), hiccoughs (P < .001), and yawns (P < .001) than full-term subjects. Both groups demonstrated greater stress during the neuromotor phase of testing. Neonatal care professionals must scrutinize the diagnostic benefit, reliability, safety, and timing of neurological assessment given expected physiological and behavioral changes in stable preterm neonates.

NIDCAP: a systematic review and meta-analyses of randomized controlled trials

BACKGROUND AND OBJECTIVE

The "synactive" theory of neurobehavioral development forms the basis of the Newborn Individualized Developmental Care and Assessment Program (NIDCAP). Our objective was to assess the effectiveness of NIDCAP in improving outcomes in preterm infants.

METHODS

Medline, CINAHL, Embase, PsychInfo, The Cochrane Library, Pediatric Academic Societies' Abstracts and Web of Science were searched in July 2010 and February 2012. The studies selected were randomized controlled trials testing the effectiveness of NIDCAP on medical and neurodevelopmental outcomes. The authors abstracted baseline characteristics of infants and outcomes. The risk of bias was assessed by using Cochrane criteria. RevMan 5.1 was used to synthesize data by the use of relative risk and risk difference for dichotomous outcomes and mean or standardized mean difference for continuous outcomes.

RESULTS

Eleven primary and 7 secondary studies enrolling 627 neonates were included, with 2 of high quality. The composite primary outcomes of death or major sensorineural disability at 18 months corrected age or later in childhood (3 trials, 302 children; relative risk 0.89 [95% confidence interval 0.61 to 1.29]) and survival free of disability at 18 months corrected age or later in childhood (2 trials, 192 infants; relative risk 0.97 [95% confidence interval 0.69 to 1.35]), were not significantly different between the NIDCAP and control groups. With the sensitivity analysis that excluded the 2 statistically heterogeneous outlying studies, there were no significant differences between groups for short-term medical outcomes.

CONCLUSIONS

This systematic review including 627 preterm infants did not find any evidence that NIDCAP improves long-term neurodevelopmental or short-term medical outcomes.